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Fix Windows Clock Drift and Time Sync Failures

A clock that runs minutes fast breaks certificates, sign-ins and file timestamps. The fix is usually one service and one server address.

by@guidox updated:10/31/26 time:15 min level:Beginner tested on:Windows 11 24H2 works on:Windows 10, Windows 11
TL;DR

Check the **Windows Time** service, then resync against a reachable **NTP server**. A clock that drifts again within days has a failing CMOS battery, not a software problem.

Before you start

Requirements

  • Admin rights
  • An internet connection
  • A terminal
Step by step

Instructions

01

See how far off it is

Compare the local time with a reliable source and note the difference. Seconds of drift are normal between syncs; minutes mean the service has not run for a long time.

w32tm /query /status
02

Make sure the service runs

The time service is set to manual on some systems and never starts. Set it to automatic and start it before you change any server address.

sc config w32time start= auto
net start w32time
03

Point it at a working server

A domain controller beats a public pool on a work network; a public pool server is fine at home. Resync and read the result instead of assuming.

w32tm /config /manualpeerlist:"time.cloudflare.com" /syncfromflags:manual /update
w32tm /resync
tipUse a server in your region. A distant one adds latency, which the client handles, but a blocked port 123 fails outright.
04

Check the time zone and the format

The clock can be right and the display wrong. Confirm the time zone and the automatic daylight saving switch before you chase the seconds.

Settings > Time & language > Date & time
05

Rule out the CMOS battery

A machine that loses time while switched off has a dead coin cell. That is a two-euro part and the only real fix for drift across power cycles.

⚠ warningLosing the clock at every cold boot also resets firmware settings. Save your BIOS profile before you replace the cell.
06

Verify after a day

Check the offset again the next day and after a reboot. A sync that holds for a day and fails after a restart points at a startup dependency, not at the server.

w32tm /query /status
Troubleshooting

Common issues

Resync fails with access denied

The command needs an elevated prompt. Start the terminal as administrator.

The service stops again after a reboot

A policy or a tweaking tool sets it back to manual. Check the startup type and any local policy.

Time is wrong only in one app

The app caches its own clock or reads a different time zone. Restart it after the sync.

Drift returns within hours

Hardware, most likely the crystal or the battery. Check the time immediately after a cold boot.

FAQ

Frequently asked

Do I need a third-party time tool?

No. The built-in client handles NTP fine once the service runs and has a reachable peer.

Which port does it use?

UDP 123. A firewall that blocks it makes every public server look broken.

How to undo this

Set the peer list back to the default with **w32tm /config /syncfromflags:domhier** and restart the service. Nothing else changed.

Changelog · 1 entry
  1. 2026-10-31
    First version
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